Stresses Beneath Pads Under Eccentric Loads, Shears and Moments Spreadsheet

Stresses Beneath Pads Under Eccentric Loads, Shears and Moments Spreadsheet

 

EccPad is an Excel spreadsheet for the calculation of pressure induced beneath rectangular pads subjected to eccentric loads, shears & moments.  The pressure distribution can be linear no-tension, linear tension allowed or uniform no-tension.
Using its analysis, pads can be sized to limit the induced vertical pressures and to have adequate safety factors against overturning in two orthogonal directions.
EccPad helps reduce design time by avoiding cumbersome hand calculations. In a design process, pad data can be saved and retrieved for repeated optimisation.
Features

  • The pressure distribution beneath the pad can be Linear-Tension-permitted or Linear-No-tension  or Uniform-No-Tension.  A pull down menu allows a selection from these three analysis options.
  • Analysis can be in any consistent units of force and length e.g.  kN m, lb ft, etc.
  • A diagram displays pressure distribution at corners and along edges of the pad on the screen display.  This allows comprehension of the induced pressure distribution at a glance when meeting design and commercial requirements.
  • The diagram also displays positions of both the axial and the shear resultants.
  • Overturning factors in the x-x and the z-z direction are calculated and shown in the screen display and output.  This allows a check of pad stability at a glance.
  • Percent loss of soffit area in compression is calculated and displayed when the analysis is non-tension.  This helps sizing of pads and improve their stability.
  • Reactions from Staad Pro or similar programs can be copied to the clipboard and pasted into EccPad.  This reduces input errors and expedites the design process.  No sign adjustments are required when the input is from Staad Pro.
  • Induced pressures are calculated at all four corners of the pad and noted in the screen display.
  • The distribution of mass in the rectangular pad can be non-uniform.  To this end, self weight of the pad and its centroid is input as data.
  • In addition to the self weight, eleven other loads can be applied in each EccPad analysis.
  • Each applied load can have 8 components i.e. Fy, Fy, Fz, Mx, My, Mz as magnitudes and  x, y, z  as their position from top lower left corner of the pad.
  • The induced pressures are calculated at soffit level of the pad.  As applied loads act on top of the pad, the additional moments equal to horizontal loads multiplied by the pad depth are taken into account in the analysis.
  • When the analysis is non-tension, the full lengths of pad edges may not be in compression.  To show extent of the compression zone, the lengths of pad edges in compression are calculated and shown in the diagram display.
  • An easy to use database facility is included within the EccPad file.  Data for up to 200 pads can be stored in a single EccPad file.
  • An Auto-analysis option allows analysis as well as printing of all or selected pads at the click of a button.
  • The pad data is kept in the worksheet STORE that is visible to the user.  Using spreadsheet features of Excel, new data can be generated and the existing one examined and or modified.
  • The template has virtually no user interface.  The printed Output matches the Screen Display.  Knowing how to use Excel and the ability to verify results as a designer is sufficient for using EccPad.
  • Green shaded cells in the spreadsheet signify User-Input and un-shaded cells signify Spreadsheet-Results.  This permits easy checking at a glance by the users and the checkers of EccPad output.

Calculation Reference
Structural Engineering

 

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Standard hook bars in tension for ACI 318-08 Spreadsheet

Standard hook bars in tension for ACI 318-08 Spreadsheet

 

ACI 318-08, Chapter 12 is the basis for this table.

The development lengths for standard hook bars in tension for ACI 318-08 is given in Article 12.5
Standard hooks (with 90-deg or 180-deg bend) are defined in Art. 7.1 of the ACI Code.

A modification factor of 0.7 is applied to the basic development length in the above table.  Therefore, the side cover (normal to the plane
of hook) for bars #11 and smaller shall be greater than or equal to 2.5″.  For 90-deg hook, cover on bar extension shall not be less than 2″.
No stirrups or ties are assumed to occur within the development length, l dh .

Standard hooks shall not be considered to be effective in developing bars in compression.

The development length of deformed bars in compression for ACI 318-08 is given by Article 12.2.3
The development length of deformed bars in compression has been calculated assuming that no spiral or ties enclose rebar to be developed.
Calculation Reference
ACI 318-08

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AASHTO LRFD 2007 – Concrete Deck Design Spreadsheet

AASHTO LRFD 2007 – Concrete Deck Design Spreadsheet

 

INPUT DATA:

  • Effective span length
  • Deck Thickness
  • Asphalt Thickness
  • Girder spacing ( S.9.7.2.3.)
  • Truck type
  • Lanes numbers
  • Reinforcement strength
  • Concrete 28-day compressive strength
  • Beton elastisite modulu
  • Concrete density
  • Asfalt density:
  • Cover
  • Bar Radius
  • Bar spacing

 

CALCULATIONS AND CHECKS

  • Dead load effects: (S.3.4.1-2)
  • Deck  Moment
  • Asphalt Moment
  • Live load effects  (S.3.6.1.1.2-1)
  • Lanes factor
  • Truck load
  • Live load moment
  • impact factor
  • Live load factored moment
  • Bending calculations  :  (S.5.7.3.2.1)
  • The pressure coefficient of the depth region
  • Moment safety factor
  • Concrete tensile stress
  • Section Length
  • Sectional Elevation Account
  • Bar numbers
  • Bar
  • Total bar area
  • Depth of stress block
  • Flexural strength
  • Flexural strength of Coefficients

Calculation Reference
Bridge Structural Design

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Snow Loading Analysis Excel Sheet

Snow Loading Analysis Excel Sheet

 

“ASCE705S” is a spreadsheet program written in MS-Excel for the purpose of flat roof snow loading analysis for buildings and structures per the ASCE 7-05 Code. Specifically, coefficients and related and required parameters are selected or calculated in order to compute the net design snow loads, including snow drift due on lower roofs and rain-on-snow surcharge.

Program Assumptions and Limitations:

1. This program specifically follows Section 7.0, Snow Loads, of the ASCE 7-05 Standard, “Minimum Design Loads for Buildings and Other Structures”.

2. This program assumes only snow loading analysis for buildings with a flat roof, or low slope roof <= 5 degrees. (Note: for reference, a 1:12 roof slope equates to 4.76 degrees, and the program allows a slope up to 1.05:12.)

3. This program addresses only balanced snow loading, snow drifts on lower roofs, and rain-on-snow surcharge loading. Unbalanced roof snow loads are not considered.

4. This program assumes the possibility of either leeward or windward snow drifts, and the larger of the two calculated drift heights per the code is used as the design drift height. Leeward drift results from snow blown off a high roof onto a lower roof. Windward drift results from snow blown against a projection or wall below a high roof.

5. This program determines any rain-on-snow surcharge loading when applicable. Rain-on-snow surcharge loading of 5 psf is not required for ground snow loads, pg > 20 psf, nor for roof slopes (in degrees) >= W/50, where “W” is equal to the horizontal distance (in feet) from the eave to the ridge on the building. This program conservatively combines the rain-on-snow surcharge loading with snow drift loading. However, per Code, rain-on-snow surcharge loading need not be combined (superimposed) with snow drift loading.

6. This program contains numerous “comment boxes” which contain a wide variety of information including explanations of input or output items, equations used, data tables, etc. (Note: presence of a “comment box” is denoted by a “red triangle” in the upper right-hand corner of a cell. Merely move the mouse pointer to the desired cell to view the contents of that particular “comment box”.)

 

Calculation Reference
ASCE 7-05 Code Snow Load

 

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US Steel Sheet Pile Design – Cantilevered Wall Spreadsheet

US Steel Sheet Pile Design – Cantilevered Wall Spreadsheet

 

US Steel Sheet Pile Design – Cantilevered Wall (Granular Soil) with Cooper E80 Surcharge

Spreadsheet Description:
Computes the depth required, maximum moment, and section modulus required for Sheet Pile Design based on US Steel’s Sheet Piling Design Manual. There is a sheet to analyze the effects of Cooper E80 loading per AREMA Specifications. However,  normal traffic or equipment surcharge loads can be used as well. Graphs are provided for Log Spiral Active and Passive coefficients.

Table of Contents:
1) Background and Instructions
2) Calculations for Pile Depth
3) Equation Solver and Graphical Check of Results
4) Maximum Moment and Section Modulus
5) Calculations and Graph of E80 AREMA Loading
6) Tables and Graphs of Log Spiral Curves Used for Active and Passive Coefficients

Instructions For Users:
1) Go to Pile Depth. Fill in white boxes with the appropriate data using drop lists

Assumptions:
1) For use cohesionless soils
2) Ground water is lowered to the bottom of excavation

Calculation Reference
Soil Mechanics in Engineering Practice, K Terzaghi and R Peck

 

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